Clockwork Heart
by cynical camp boy
Summary: People... They're getting ripped from their timelines. It's... Unnatural. The timelines, of course, they reject them. Almost nobody gets away without a scrape, without something being taken away from them. And... Most of them, they end up dead or barely alive the second that they come out into their new timeline. But at least I'm here to try to keep them alive. (AU created by me.)
1. Into the Between

" _People... They're getting ripped from their timelines. It's... Unnatural. The timelines, of course, they reject them. Almost nobody gets away without a scrape, without something being taken away from them. And... Most of them, they end up dead or barely alive the second that they come out into their new timeline. But at least I'm here to try to keep them alive._ "

* * *

"... Where am I?" Undyne whispered, sitting up slowly and nearly screaming out of pure agony. She gritted her teeth, suppressing it as much as possible, and holding out her arm, lighting up the nearly impenetrable darkness with the glow of a light blue spear. She held it high, waving it around to take a look at everything. It appeared to Undyne that she was deep in a cave, water dripping all around her. Huh... Her light illuminated something a sickly white color, standing out from the pale cream and brown of the dripping cave walls around her. As she moved it, she felt a shiver run up her spine. It was a human skull, rolled long off of its main body. Usually, Undyne would be happy to see a skeleton, but this definitely wasn't Papyrus or Sans. Undyne stood up shakily, commanding herself to shut up and stay calm, standing the pain. She drew the light down to her legs, and she took a deep breath upon seeing both of her legs, gashed and sliced. Hell, one of them looked like it was about ready to fall off. Apart from her own condition, Undyne realized something else. This water wasn't clear at all. Instead, it was a murky white, and bits of dust flew through the air. Other human skeletons decorated the cave, and Undyne stepped out of the water. "Okay, lets see here..." She muttered to herself, stepping onto a path of oddly smooth stones that stood out of the dullness of the regular cave landscape. Undyne bent down slowly and carefully, dipping her hand into the water and bringing it even closer to the light. "... This is... This is filled with the dust of monsters. By the Angel, I'm... In a death trap. For humans and monsters!" She realized, stumbling farther onto the path.

Her heart thumping, Undyne took a shaky breath, glancing at the arm that wasn't holding the spear that lit her path. At least it wasn't mangled like her legs. But then again, you can't walk on your arms, can you? Actually, Undyne figured, she probably could walk on her arms but that was a completely ridiculous notion, especially in this situation. "... Guess I should follow the path." She breathed, staring down at the path as she walked, lecturing to herself to keep moving. These stones all looked almost exactly the same, and that disturbed her. What disturbed her more was the amount of dust floating through the air, obviously from dead monsters, and the mangled remains of long dead humans. Huh. If she survived this and was able to come back, she might be able to catch a human and bring more SOUL's to Asgore. Undyne knew that she was at least underground, but that didn't mean she was in the Underground, which pissed her off. Undyne shook her head to clear her thoughts and just focus on getting out of here. She swept the spear in front of her, her thoughts pinpointing only the sound of her own footprints, her breathing, and her heart... So it wasn't much of a surprise when Undyne became acutely aware of animalistic growling echoing around her. Undyne sighed in mere frustration. Why. Why now? She sped up her pace, attempting to outrun whatever seemed like it wanted to have her for lunch. "Not today, not today, not today..." Undyne whispered to herself.

And the something decided that it was today. Out of the shadows, it slammed into the stones jutting from the cave floor, and Undyne let out a yelp of surprise. It turned on her, its gray weaved fur sparking. Its eyes were an odd combination of blue and yellow, and a beady pupil stared at her. It cracked open its jaws to roar right in Undyne's face, and she got a good look at its long rusted and jagged teeth, and abyss black maw. "Okay, hello there!" She yelled to it, and it snapped its mouth shut, narrowly missing her. She raised her good arm, attempting to slam the spear into its maw, and it disappeared with a crack of magic. Channeling what she had left in her, Undyne lit up the tunnels with spears, shooting towards the beast. It honestly looked like a huge wolf to Undyne at the moment, but she didn't have time to think about what the thing she was fighting was, just the fact that she was fighting. It stabbed straight into the beast, and it howled in pain for only a moment. It turned on Undyne, whose eyes widened in surprise, and it raised a paw, slamming it into her. She flew into the cave wall, letting out a yell that echoed around the halls. It snarled, opening its massive mouth again and clamping down onto Undyne's bad arm, lifting her into the air like a rag doll. It flung her into the opposite wall, and Undyne was dead silent, rolling onto the ground. "You're going to have to try harder than th-" Undyne started, but two beams of light pierced through the cave, completely illuminating everything in front of the lights.

"Stop. Don't do that." A clear voice said, and Undyne immediately shut up, gritting her teeth. "Lay still. Don't let the Errim see you. " The beast, apparently an 'Errim', turned towards the light, and snarled, prowling towards it. The lights shut off and on, as if the thing behind them were blinking. "... H-Hey there buddy." It whispered. "Come over here... Come over here towards the light... There ya go..." Lines of drool flecked the Errim's face, and it opened its jaws to snarl as it leaped forward. Undyne was about to get up, to help the person who had saved her, when suddenly, a bright arc of light sliced through the Errim. It snapped its jaws again, reaching a paw out towards the lights, and that was the last move it made. It was split clean in half by whatever that person was wielding, and its split sides disintegrated into black dust. All was silent, until the click of claws on the floor from the person walking towards Undyne rang through the cave. "A-Are you still alive? I really hope so. You'd be the first one... And, uhm, m-maybe... I wouldn't be alone anymore?" It asked politely. Undyne's ragged breathing was enough to answer its question. "Still kicking... Uhm... Just as a warning... When you wake up... E-Expect... Numbing, or loss of feeling in your limbs or other parts of your body. Sorry." It said, and a needle came into the light, quickly piercing Undyne's scales and pressing some green colored liquid into her. And before Undyne could ask any questions, she was out.

* * *

Undyne hadn't remembered much after being teleported into that place, of twisting endless caverns, with the paths of smooth, round stones. But one of the things she had remembered... Maniacal laughter Undyne had heard pierced her thoughts, and she opened her eyes, to find herself standing in front of a human child, wearing what appeared to be an extremely formal suit and a top hat, decorated with stripes. What Undyne noticed the most about that, was the amount of metal on this child. What did it remind her of? Oh, yes, Steampunk, she thought the name was. "Like my new outfit, Undyne?" They asked, pointing a huge butcher's knife at her. "Don't answer that, I know I look better than you." They shrugged. "Anyways, I hope you had fun with... Huh. What did she call them? Oh, my 'Errim' puppy. I've got many more of them, so just because that one's dead doesn't mean you're completely off the hook! But off the topic of that, nice job living through the timeline switch!"

"Timeline switch? What?" She exclaimed in surprise.

"That's right! I ripped you out of that normal, boring place like you were a sticker, and slapped you into here! As you may or may not have noticed from my decorations, I've tried it before, but... Only a few people have survived. And even then, barely." They shrugged. "Aw well. I mean, the good thing is is that, you lived, huh? Anyways, the point is, is that I'm gonna tell you something before I'll be forced to be cut off from bugging you for quite a while."

"Cut off? Wait, what do you mean?" Undyne questioned them, and they took a deep breath.

"Mmm, due to a few things that will happen to you... I won't be able to contact you. And besides, I might let information slip! And that's no good to the fun. Anyways, the thing is... Is what I just wanna tell you... You're never ever going to be able to get back into your home timeline, and if you try, you'll be ripped apart. Feel free to toy around with other timelines though. After all, I made this place for fun! And that would be really fun!" They laughed. "But good luck finding out how to move timelines. But until then, you're stuck here. Sit back and have a good time, Undyne. I'll be watching you." They raised their knife, and that was when Undyne realized that she was unable to move. But of course, there was nothing she could do, because the knife was sliced down onto her, and her sight slammed back into the darkness.

Now there was nothing she could do but wait and hope to wake up.

* * *

The black was suddenly pierced through with a slice of light, not dissimilar to the one used to kill the Errim earlier. Undyne jolted up in surprise, her head colliding with someone else's. Obviously, they let out a yelp of surprise, falling onto the floor with a clang of metal on dull stones. Undyne blinked, clearing the light and raising her hand to rub them. Instead of her own hand, she felt metal against her eyelid, and stopped in a panic. "What happened?!" She exclaimed to nobody in particular, throwing off the sheets that had been used to cover her. Her vision now clear, she realized that something was very, very wrong. The arm that the Errim had mangled was now no longer flesh and blood, but metal. Undyne raised her other arm, sighing in relief upon seeing her own blue scales. Thank goodness she had that left. Speaking of seeing, she also noticed that her left eye, the one that she had always worn an eyepatch over, had some odd modifications as well. But she could have depth perception again, so that was nice. On top of all of that, both of her legs had been replaced in the same way her arm had. "... You, what did you do?" She turned to the figure, who was currently dusting themselves off and rubbing their head. It was too dark in here to see who it was perfectly, but Undyne could tell that it was short and its arms looked rather flimsy. AKA, easy to beat into dust if necessary.

"I'm really happy you're awake, I was, uhm, r-really worried that maybe only your heart was beating... I mean, I kept winding you up, and uhm, the heart monitor was on, but maybe it was tricking me because I don't think that the tech I've got down here is very reliable..." Undyne could tell that the voice was female, and she decided to stand up. On new legs, that was probably a very bad idea, and she stumbled, nearly falling if it wasn't for the little thing running over and catching her. "Sit down, o-okay? Sorry that it's so dark, the Errim, they're attracted by the light... I wasn't sure if you'd be okay, with, you know, both of your eyes being replaced, so I just fixed the bad one."

"Wait, you did this to me? And, winding up?" Undyne asked her incredulously, sitting back down.

"Yeah, I did. An Errim's bite almost immediately surges poison through your body, therefore rendering your limbs completely useless. And if, y-you somehow survive the initial bite, and get away, the poison from the bite will spread through your entire body stunning you permanently. And that's why I replaced your arm. And, uhm, your legs too. Because, they weren't... Doing too well. And, about the stunning permanently thing... Sorry."

"What do you mean, 'sorry'? What else did you do to me?"

"The poison had already gotten to your heart, so... I... Had to replace that too. So, uhm, the complete list of what I did to you would be... Replacing your eye, your arm, your heart, and your legs." She explained to Undyne, nervously. "I, uhm, d-d-didn't know if you wanted to live or not so, uhm, I did it anyways. There's, uhm, something special about your new heart that I should probably tell you, but maybe we should save that until you're a little more settled in... It has to do with one of your, uhm, p-previous questions."

"... By the Angel you're a life saver." Undyne said. "In normal circumstances I would be furious, but seeing as this basically saved my life... Thanks. I'm Undyne. Who are you?" She introduced herself. The person scuttled off for a few moments, tapping something in the stones, which suddenly lit up the entire room. Undyne squinted to adjust to the sudden light, giving the person time to walk back up to her. And Undyne saw a reptile monster of sorts, except about the only organic part of her was her head and one of her arms. However, the hand on the regular arm was replaced to be robotic. Her eyes were modified to be electric, her arm reminding Undyne slightly of the way Mettaton's arms worked. Her body was pure metal, with a simple heart rate displayed on her chest, with a yellow heart and line tracking her heartbeat, which meant that she hadn't replaced her heart. Her legs were, again, robotic, and her tail was made up of many flexing parts, making her tail probably deadly in a pinch.

"Oh, an Undyne!" She said like there had been many more of her that had fallen into this place. "Hi there, Undyne number 18!" That confirmed her suspicion. "But th-that's probably too formal. I'll just call you Undyne, and since we're gonna be informal, I might as say my informal name too..." She took a deep breath, raising up her flesh and bone hand for Undyne to shake.

"My name is Alphys!"


	2. Decisive Path

Undyne stared at Alphys, blinking multiple times and opening her mouth to say something, before quickly closing it. You know, like a fish gasping for air. "Alphys?!" Undyne yelled, and Alphys nodded slowly. "Wait wait wait, okay, no. No, that can't be. If you were Al, you would make your mechanical gizmos really anime, really flashy and cool." Undyne started to pace back and forth, trying to get used to her new legs and take in all of the information she was being bombarded with.

"Light attracts the Errim... Besides. You shouldn't sacrifice convenience for style, especially when nobody else is there to see it. It's just... Useless to indulge in these sort of petty things." She said, her gaze dropping to the floor.

"... Well, okay, how did you even make these modifications without killing yourself?" She asked, raising an eyebrow.

"Other Alphys' that have fallen down into here. Well, only one survived, and I got her to help me. That Alphys was bound to die anyways, and she accepted it. While she still had time, she helped me, so at least I could survive and keep protecting people." She said dully, her slightly robotic voice chilling Undyne. It did seem, however, that she was getting used to talking to Undyne, losing some of her stammering and nervous tone.

"Okay, fine. I give up..." Undyne mumbled. "... But what's with the whole other Alphys, other Undyne, doubles thing?"

"Finally, a-an easy question!" She said, a mechanical hand coming out of a capsule on her completely robotic arm. "Okay, okay, uhm... Oh, here, I should just sh-show you." She explained, and small device popped up alongside her arm, with a small bulb on the end of it. It whirred to life, and a projection appeared on the stone wall. "Alright, uhm, lets see, where to start. Right! Okay, so, uhm, there's a kid, and I think their name is Chara. They're a human, of course. They figured out how to shatter timelines, break them, ruin them. Like, for example... Your timeline, you got pulled out of it, therefore breaking it from the normal timelines... Wait, tell me what everyone looks like, was it a normal timeline?" Alphys mumbled.

"Papyrus had his battle body and that orange scarf, Sans always wore a blue hoodie and black shorts, my... 'Timeline's' Alphys wore glasses and a labcoat, and Asgore wore this silver armor with this huge purple cape." Undyne quickly listed off a few people off of the top of her head. Alphys nodded.

"Right, so it WAS a normal timeline. I mean, at least until Chara pulled you out. You see, this place is called the Between, it's basically like a little tiny... Erm. Universe. Not exactly a timeline, because it isn't even in the Underground." Alphys explained to her, pointing to the various diagrams that she had pulled up on her projections.

"Pocket dimension?" Undyne asked, and Alphys clapped her hands together, making the projection shift and waver for a moment.

"Yes! Pocket dimension, that's a perfect way to describe it. Basically, the Between is a sort of purgatory hell place that Chara drops some of us off to, to, you know, play with us. That's why the Errim are here. They basically keep us on our feet, keep us entertaining to Chara. But only a few have survived, and to be honest, after all of my time in the Between, I've started to think that I'm probably not one of the only ones... But that's off topic!" Alphys rambled, clearly losing direction in her lecture. "Okay, okay, back on topic. You asked why there are doubles and stuff, right? Don't answer that. Basically, there's tons of timelines with countless versions of, well, us. So like, you're one Undyne, but in another timeline, there's another Undyne. Get it?"

"I... Guess so." Undyne answered.

"Okay, good. So, to explain all the dead things you saw, those are basically other versions of us and other monsters. Every time I've seen a Sans fall in here though, they just... Disappeared. It's weird. Anyways, I've identified quite a few of the bodies. Come here." Alphys said, the projection stopping and folding back into her mechanical arm. She sat in a chair and rolled over to another wall of the room, half of the wall covered in monitors. "Okay, so the dust water you fell into was mostly composed of, of course, water, and quite a few Papyrus, Alphys, oh, and I think a Toriel one time. I've lost count. It's not really hard for me to believe there are my doppelgangers out there, since one helped me once. So basically, this is the story." She explained to Undyne, her robotic fingers darting over the keyboard, zooming in and out of the dust water lake, scrolling over to human skeletons, and pulling up countless diagrams. "I was getting situated in the Between. I had one foot in the grave most of the time, and I barely survived being put in here, since getting ripped from a timeline literally rips you apart. How grim, huh? Okay, anyways, I had set up a little way for me to check if someone else fell in. At the time I had made only one camera, so of course I set that up. There was this huge yellow flash, and right away I could tell that it was an Alphys. I decided to go help her, and, like me and you, she was from a normal, base timeline. I explained to her what I thought was going on, and she agreed to help me. Most of the Alphys that fall down into here usually bite the dust right away, die of loneliness, or get ripped to shreds by the Errim. But this one was different, in that, she accepted that she was probably going to die, and decided to help me live instead. Brave one, she was. She could barely stand when she came into the Between. I led her to the little makeshift lab we're standing in right now, and she helped me make the body modifications you see on me."

Undyne nodded, trying to follow Alphys' rambling, but found it extremely hard to do so. Oh well. What can you expect when you're talking to Alphys? Oh, sorry. AN Alphys. "In any case, it was painful because there really aren't any painkillers down here... Oh, I'm so sorry, I got really really off topic there, I'm sure you have a lot more questions than just, why are there more of us?" She quickly apologized. "But first, I really should tell you something about your new body parts." Undyne let out a sigh of relief. She didn't blame Alphys for rambling on as much as she had, because of how little she was able to talk, but it did seem like they were wasting time. Alphys walked up to Undyne, grabbing the collar of her shirt and yanking it down slightly.

"What are you doing?" She questioned, leaning away from her in surprise.

"Hold still!" Alphys said. "Okay, give me your hand. And you see this little lock looking thing in the middle of your chest?" Undyne quickly gave Alphys her mechanical arm, nodding at the same time. "That is your lifeline. It's a mechanism that winds up your heart, like you would do with... Say, a music box."

"Wait, you mean I have to... Wind up my heart? What is it, clockwork?" Undyne yelped in surprise.

"Well, yes actually, it is clockwork." Alphys answered, pressing a button on Undyne's palm.

"That was supposed to be a joke..." Undyne mumbled.

"Anyways, you see the button I pressed on your hand. Okay, press that and this little key comes out of your palm, like so." Alphys pulled a little wind up key from Undyne. "And you just put it into the lock, and wind it up. Simple and easy."

"... Why didn't you just make me a heart that did all this stuff automatically?" Undyne asked, taking the key from Alphys.

"I don't really have the resources any more to do that like I did with mine." Alphys said nervously. "But that's not the only thing about your heart. If you wind it up past what it needs to be, it will overcharge. Make you faster, stronger, get where I'm going with this?"

"Hey, at least I got that." Undyne said, putting the key into the lock.

"No no no, wait! Only overcharge when you NEED to. It's not good for any of your mechanisms to stay overcharged like that for too long."

"Got it." Undyne said, quickly taking the key out of the lock and pressing it back into her hand. "Well, this seems easy enough... But is there a way out of the Between?" She asked Alphys.

"Oh I thought you'd NEVER ask!" Alphys said, putting her hands on the dusty desk and rolling over to another large table, which had none of the large monitors the other had. "You see, we need to stop Chara from putting people into the Between, and save and help the ones that do fall in. When they're fit to go, we try to insert them back into their old timeline, at exactly the moment they got ripped out. But in our case, we can't go back."

"Wait, you mean I'll never get to cook with Papyrus again? Train him? Hang out with... You?" Undyne said, becoming extremely nervous.

"Listen Undyne, how well do you think someone would react to one of their old friends, looking fine one moment and then appearing horribly disfigured the next? We're not going to mess with the timelines like that." Alphys explained to her, and Undyne's gaze dropped to the ground. "Chin up, a Papyrus might fall in here and he might actually survive for once!"

"I don't like those odds." Undyne replied, and Alphys sighed.

"Okay, let me just explain the mission to you one more time, quick and simple. Our main objective is to defeat Chara, but we don't have enough people to do that. There's only us. Apart from that, we need to fix the timelines, set them right, you know? We don't want timelines to be suddenly missing a Toriel, Sans, Papyrus, Undyne, Alphys, Asgore, you get the idea. That's just going to doom them. If anyone falls into here that will survive without having the modifications we have, they get sent back. Otherwise, they have to stay here in the Between to help us fight Chara. There's also little time rifts that need to be sewn closed, and even people who break the timelines other than Chara. And you need to stop them permanently. We need to preserve the timelines as best as we can, despite how fractured they are..." Alphys explained to Undyne, as if she had recited it several times.

"Wait, why do I need to stop them?" Undyne asked her.

"You have fighting experience, you have your overcharge, you're strong, unlike me. Besides, someone needs to hold down the fort and help the people who fall into here, and monitor the timelines as best as I can. Maybe when we get more people in on this, you can take a break, but until then, it's up to you. Are you up to the challenge?" Alphys said. Undyne burst out into laughter, and Alphys squeaked in surprise, dropping a mountain of papers which cascaded to the floor.

"Hah! A challenge? Don't make me laugh more than I already have! Nobody challenges Undyne the Undying and expects to win!"

"Guess I used the magic word, huh?" Alphys asked, beginning to pick up the papers.

"Damn right! Now, Al! Tell me which timeline to hit, where to go, and who to eliminate, and it's done!"


	3. Felling Horror

"As much as I would like to say it's as easy as that, it isn't... I need to scout around the timelines, search for the right place to g-" Alphys begun to explain, until suddenly, a single loud beep came from Alphys' computers. "... Or maybe it may be a little bit easier." She whispered, walking over to the computers and clicking through the screens. "Oh boy, okay... Two anomalies have appeared in..." Undyne rushed over to her side, and Alphys leaned away from her. "Horrortale... I'm not really sure if I should send you there, especially since you're still recovering... A-And since it's your first..." She mumbled, pointing to a static filled screen, probably a camera.

"Horrortale? What's with the name?" Undyne commented.

"Names have been assigned to the timelines, some I came up with myself, others I've found out. The base timelines are called 'Undertale'. Get how this system works?" Alphys explained to Undyne, who snorted, honestly thinking that that was a stupid name.

"Anyways, 'Horror'. I don't get easily scared. I bet it'll be like some trashy haunted house." Undyne said, leaning against the desk. Alphys narrowed her eyes, poking the screen with a robotic claw. The camera showed a snowy forest and a large door, covered in thick vines. Even without audio, Undyne could tell that there was something pounding at the door, throwing itself against the door to break out. She leaned in closer, staring at the door very closely. For a moment, the door opened, and a white, thin hand reached through the tangles of vines, clawing into the forest. Static shook the screen, and when it stabilized, a shiver ran up Undyne's spine. This camera was facing the door head on, and Undyne could clearly see a pair of dull eyes, a burst of fire, before the door snapped closed, and the hand quickly thrust back into the shadows. "... Not scary at all."

Alphys let out a heavy sigh, standing up from her chair, leaving the feed of this 'Horrortale' up. "Fine then. Since you're so ready, I'll give you a few more pointers on what you're supposed to do while you're there, and how to get back to me." She said. "Follow me." Alphys muttered, beckoning to her. With one last glance at that image of the monster trapped behind that door, Undyne walked after her, her enthusiasm slowly fading. It didn't take long before Alphys stopped in front of a very old and dusty looking pad. Undyne raised an eyebrow, leaning down to touch the mechanisms that weaved intricately through its thin surface. Before her finger could even graze the thing, Alphys reached out a hand, pulling it away. "Don't touch anywhere but the top of the pad p-please!" She said, quickly letting go. "Anyways, uhm, you gotta solve these anomalies. My computers read them as extra anomalies, also known as two things you need to remove from Horrortale. You cannot remove or add anything else to the timeline, or have to go back and fix them. Got it?" Alphys asked her.

"Sounds easy enough..." She shrugged, wincing at the odd feeling of her metal shoulder as it grazed her face. It was unnaturally cold, and it disturbed her, after being so used to having two flesh and bone arms.

"Good. Now, to return, you will be taking this little doodad with you." Alphys said, reaching over to a table and pressing what appeared to be a gear into Undyne's hand. "There's a button in the middle of it, and if you press it after all the anomalies are cleared, you will be sent back to the Between. But only if every single anomaly is cleared, okay? I will have very loose contact with you while you're in Horrortale, and I won't be able to guide you."

"Sounds a little too free to me..." Undyne mumbled, tucking the device into the remains of her jeans from her home timeline.

"You can always back out. I mean, you're the one who was so confident..." Alphys mumbled. Undyne raised an eyebrow, crossing her arms. "While you're there, one last time, get rid of these two anomalies, and return safely. Nothing else, nothing more. Oh, and... Maybe if you happen to run across clothes that fit you, you might wanna get them. Your trip into the Between didn't really help with that something." She muttered, before running back to the desk, which Undyne noticed was lined with buttons. Alphys clapped her hands together. "Alright! Lets fire this thing up! Just need to input the exact coordinates of where to place you, in what timeline, and, in what time in the timeline."

"In what what in the what?" Undyne whispered.

"In what time in the timeline." Alphys repeated, as if that explained anything. She hit a red button, and the pad fired up, beginning to glow a soft yellow light. "Alright, get on and get going! I have everything ready." She said, pointing to the pad. Undyne stepped very carefully onto the top of it, and the yellow light immediately flushed to a dark green, as if it recognized exactly who she was. "Good luck Undyne, and don't you dare die!" Alphys yelled, before pressing a few more buttons. The green light flared up to a blinding spotlight, and just like that, it died down back to the yellow light. Undyne was gone. Alphys immediately ran over back to the computer she had left on, and nodded in satisfaction upon seeing her right in front of the camera, dusting snow off of herself. "Step one, get into the timeline, done. Step two, find the anomalies, commencing."

* * *

The landing had been rough. Undyne kind of wished that Alphys had given her more of a warning when she had dumped her off into this timeline, instead of slamming a few buttons and not even counting to three. Undyne stood up, brushing herself off with her mechanical arm. A clatter and creak from it immediately made her stop, stretching her arm out in front of her and furrowing her brow. That was definitely not normal. But, like Alphys had explained to her, she couldn't come back until she had cleared the anomalies. Undyne trusted the robotic version of one of her best friends, saying one of, because if Papyrus found out that he was anything less than a best friend he would probably guilt trip her, and she trusted her enough to know that she was functioning perfectly right now. Probably... Maybe. Undyne lowered her arm, taking a look around, realizing that she was close to that banging door. It rather intrigued her... And maybe it was an anomaly trying to get out? Undyne walked up to the purple door, ignoring the slightly creaky movements of her legs, and raised a hand to knock on a part of the door that wasn't laced with vines. She cleared her throat, knocking as loudly as she could. The slamming from the other side stopped for a moment, and a thin, whispering voice reached Undyne's ears.

"Is that you, my child?" It whispered, its tone dipping into anger at the end, and a bang came from a lower part of the door, making it clear to Undyne that it had kicked the door. "Have you come back to me? Have you come back to plead for protection?" The hitting eased up for a moment, and the door cracked open. "Come in here, child. I won't hurt you..." It breathed. "Don't leave me here... All alone..." An unnaturally thin hand reached through the slight opening of the door, stretching the vines to pry it open as best as it could. "Come in..." Undyne finally caught a good look at the person behind the door. A monster woman, whose face was gaunt from what Undyne could only assume was many, many sleepless nights, stood there, a chillingly sweet smile on her face. Her dull red eyes narrowed in confusion when the person standing at the door, wasn't who she was expecting, but that smile didn't move an inch. It was as if it was plastered on, and Undyne wouldn't be surprised if it actually was. The woman's eyes moved up to meet Undyne's, and she pushed harder against the vines, freeing enough of a gap for her to reach her arm through. Undyne was about to jerk away when the white hand lashed out, grabbing her by the neck and pulling her back. "You... You are not..." She whispered, almost pressing Undyne's forehead against the door. Undyne raised her hands up, trying to pry the iron grip of the woman's hand from her throat. It merely tightened, and Undyne let out a choking gasp as it slowly closed more, and more. "You... You're..." The woman muttered, and Undyne raised her heavy boot, kicking out at the door's middle. She hit it dead on, and the door closed on that monster's arm.

The woman let out a scream of surprise and pain, letting go of Undyne. Undyne fell back onto the cold snow, raising her flesh and bone hand to her throat as she gasped for breath. The doors slammed shut once more, before continuing the slamming with reckless abandon. The vines seemed to pulse in a disgusting way, sliding to twist and tighten the closed door. "... I can see why this place is called Horrortale now..." Undyne gasped thickly, rubbing her throat. She definitely didn't want to knock on that door again anytime soon. She got up slowly, deciding she'd better try to not interact with many more people in this twisted timeline, and hurry up to find the anomalies. Doing that would be easier said than done, because asking around would probably give her a lead. Undyne sighed, deciding to talk to at least one or two people before moving on. She stepped through the snow, turning her head to look around her. Undyne noticed an odd but familiar sight, one she often saw on her checks on Papyrus and the Canine Unit, both of which resided exclusively in Snowdin. Snow dogs twisted around this path, and Undyne thought that it would be a safe bet to check them out. After all, if the person who had made these was around, she would be in luck.

Undyne raised her mechanical arm to run her hand along the neck of one of the snow dogs, sighing at the fact that she couldn't feel anything in her metal fingers. She stared at the tracks in the snow for a few moments, before noticing that they started to bleed a dark red color. That definitely wasn't disturbing or anything, no, not at all. The 'blood', or whatever it really was, ran down the snow dog's neck, and Undyne turned from the sight, quickly marching off down the path again. It wasn't long before Undyne noticed something. A sheen of silver armor, that she knew all too well. Undyne probably would have cried had it not been for the fact that Alphys was probably watching her. There was a friendly face in the midst of all of this... Horrible chaos! Undyne immediately walked up to the seemingly normal Lesser Dog, who panted and stared down at her. She gladly raised her hand to pet it, knowing that was exactly what it wanted. Lesser Dog began to lean down to meet her hand, and Undyne saw something she never wanted to see again. The dog's neck split open at a grotesque angle, blood pouring out of it. But no, it kept going, its neck extending. Undyne could see the muscles and the veins that stretched. Undyne instinctively pulled her hand away in a blind panic, breathing heavily, as the dog's neck twisted around in an odd sort of spiral, until its head touched her hand, rubbed against it. Blood began to drip down Lesser Dog's head, and Undyne merely stared in horror as the red river snaked down its forehead, finally meeting her hand. She pulled her hand off of the dog's head, waving it in the air to shake off droplets of blood onto the ground. "I really... Really don't want to be doing this anymore..." Undyne whispered, looking back up at the dog, who tilted its head, its own blood dripping out onto its tongue, lolled out from its mouth. "First mission and it had to be this place... Alphys was right, I wasn't ready for this... But I can't... Get out until I'm done!" Undyne growled. "... See you around, Lesser." She mumbled, walking away from the dog.

The horrible sound of sliding flesh reached her ears, and the almost adorable puppy face as long as you forgot the fact that it was covered in its own blood, reached in front of her. It let out a bark, and Undyne turned back to the dog, sitting down heavily in the snow. "What do you want? More petting?" She asked it, trying to ignore the blood that melted away the snow under the dog's exposed dermis. A chill ran up the fish lady's spine, not just from the snow, and it barked again, this time, warmly. "... Hm... I guess... I guess you're cute, in a morbid, disgusting kind of way. Fine. I'll give you a few more pets, but only for a deal!" She said, and Lesser Dog tilted its head, its small black nose twitching, as if to ask her what she wanted from him. "I will pet you, but only if you show me anything odd going on around here. Do we have a deal?" Undyne asked him, and it barked again, its neck slowly sliding back into its body. Undyne didn't want to know where all of that extra muscle and flesh went when it went back into its body. Maybe it was like a certain blue police phone box. No, that'd be stupid. It was magic, of course. Duh. Lesser Dog began to walk off into the woods, straight out of the clearing of long-necked snow dogs, and Undyne followed cautiously. The dog stopped for a moment for her to catch up, and she put her hand on its head. Apparently she had to pet it as they were walking. They began to walk off into the shadows, but not before Undyne heard something drop with a crunch into the snow. The head of a snow dog had fallen off, and Undyne swore she saw bones in its neck. Saying this place freaked her out was a massive understatement.

As they walked, Undyne started to become acutely aware of a horrible smell, and a mere glance at Lesser Dog confirmed that he smelled it too. This must be the odd thing Lesser Dog was leading her towards. Lesser Dog suddenly stopped, and Undyne glanced from his face down to the snowy ground. "... Oh." Undyne mumbled. "... I'm not sure why I'm surprised anymore." She raised a hand to rub the eye that Alphys had repaired for her, staring down at the mangled body of some poor soul before her. Lesser Dog whined, and allowed Undyne to take her hand off of his head. Undyne walked towards the body, ignoring the stench. "Maybe you have clues about these anomalies..." She whispered, taking her hand from her eye. A loud tick came from it, and she winced in surprise. An urge came over her to walk away from this body, farther into the forest... And she heard voices. "Thanks Lesser Dog." Undyne managed to say, taking a deep breath. "Maybe one day I'll have to come back and pet you again." She said, walking past him, before breaking into a stiff run, bolting off into the twisted darkness of the woods once more. As she got farther into the voices, she could finally identify a pair of extremely similar voices.

"this place is so damn creepy... why did ink have to send us here? why not the new guy?" One mumbled, and Undyne narrowed her eyes, listening harder. There was something so familiar about the way these people spoke, yet she couldn't place it.

"i guess he trusted us with this the most... lets see, strange going-on's in this timeline. i think i can guess what it is already." The other said, and Undyne edged closer.

"what's that, outer?" He addressed his partner, apparently named 'Outer'.

"fell, come on, it's obvious. it's almost always a sans. we just need to find horror, take a look at what he's doing, and if he's not doing anything weird, then it's not him." Outer replied. "come on, lets get this over with, i don't want to be in here longer than i have to."

"jeez, me too." Fell muttered, and Undyne leaned out of the woods, her eyes widening. They were both... Sans. One with a large crack in his skull wore a black and yellow hoodie, with a red shirt. He wore a pair of black shorts with yellow stripes on them, with black and red shoes. The other wore a dark blue hoodie with bright yellow fluff on it, light yellow stripes on the pattern. His shorts were striped with yellow, just like his companion's, with a pair of dark blue and yellow sneakers. The two began to walk off, and Undyne began to follow them through the cover of the shadows. Two Sans. Two anomalies that definitely didn't belong here. But they had mentioned something else strange in this timeline, and maybe Alphys would want to know about it. Laying low and watching seemed to be the best course of action, so that was exactly what Undyne did as she followed them. "do you hear his tapping?" Fell whispered.

"we're close." Outer replied, and the two sped up. Undyne heard the tapping they were talking about, gritting her teeth at the sound of it. After a few moments, Outer held out a hand to stop Fell from going any further, and they peered out from the shadows at a lone stand in the woods, where yet another Sans sat, drumming his fingers on the splintered wood of his station. This one definitely belonged to this timeline, and Undyne decided she'd better give him a name other than Sans. Horror. Yeah, that fit, and it appeared that the other two Sans went by the same name rule she had just used. It was odd to see three versions of one person in one place, and she was sure these two thought the same. She began to edge her way out of her cover, ready to confront them, when a sudden blast seared through the woods, and Fell and Outer let out a gasp of surprise, ducking for cover.

"i'm not sure how you thought that was camouflage." Horror said, his eyes drifting over to Fell and Outer as they stood up. "bright yellow seems to be a theme for both of you." He stood up, walking towards the two Sans as he passed by a large, rotting skull, not in the shape of any animal or person Undyne had ever seen. Definitely the source of that blast that went off earlier. "let me guess, ink sent you."

"that's obvious." Fell growled, another skull, this time almost fully intact, appeared with a flash of his red magic. "you're the source of all these problems lately, aren't you?" He asked Horror, who shrugged, watching as Outer summoned another skull as well. Suddenly, Horror had appeared in front of the two, an axe in his hands, and a huge smile on his crooked face.

"listen, you don't belong here, and i sure as hell don't either. this might be horrortale, but it's not my horrortale." He snarled. Outer and Fell exchanged a look of confusion.

"two horrortales?!" Outer exclaimed in surprise.

"like you said, that's obvious. there's countless base timelines, and there's countless alternates. i couldn't even begin to count the amount of horrortales there are. but this isn't my horrortale. i had to replace the guy who suddenly blinked out of existence in this timeline. And now that I've told you this, I think I have to serve up one of my favorite things. One head dog, coming right up!" He yelled, taking a swing at Outer, who quickly darted backwards, his blaster firing off a beam of white light. Horror easily dodged it, raising his axe again to behead Outer, when a sudden blast from an odd device Fell quickly took out made him suddenly disappear into nowhere. Undyne had a feeling that it had blasted Horror far, far away, or out of this timeline, like a mini, compact version of the thing Alphys had used to take her here. The two Sans stood, staring at each other as the axe that had been in Horror's hands, as it dropped to the ground.

"i-i was fine, you know, you didn't have to do that." Outer managed to say.

"oh god, what is ink gonna say when he finds out that i merely zapped the problem away? we need to get back right now and track him. who knows what he's gonna do!" Fell said, and Undyne decided to make her move. "lets go, before this gets even worse than it already is." He stammered, fumbling with the device in his hands. And that was when both Outer and Fell felt a hand clamp down onto their shoulders, and the face of someone not belonging in this timeline leaned down, a smile on her face. Fell dropped the thing into the snow in surprise, and they both turned to look at who it was.

"Hello there boys." She said, her mechanisms audibly ticking like a clock. "I'm here to clean up two anomalies, and what have I found. A pair of Sans, hunting down another Sans, and they're in the wrong timeline." Undyne whispered. "You two don't belong here."

" _So, tell me. Do you want to do this the easy way, or the hard way_?"

* * *

 **AN: Right now Clockwork Heart is collaborating with another very good fanfiction, called Metal Mask, by Ckbrothers. I strongly, strongly suggest you check it out, since both Clockwork Heart and Metal Mask tie into each other.**

 **In other words, when the collaboration arc is over, submitting AU's and problems in them for Undyne to fix is a viable option. It's only a matter of time before I run out of ideas for AU's for Undyne to go into, and that's where my readers come in. Like I said, submit a large AU, submit your own AU, and it might get in. And I say, might, because I want this story to have some sort of storyline in it, other than, Undyne goes and fixes timelines, because that wouldn't make for a very interesting story, now would it?**

 **In the meantime, please enjoy.**


	4. Somebody New

"You two definitely don't belong in Horrortale. What are you doing here?" Undyne growled, staring down at them. "You're definitely these... Anomalies that I need to get rid of." She said. Outer reached into his pocket, and Fell shrugged.

"well, the thing is, i don't really think you know who the hell we are." Fell laughed, raising his hand to snap his fingers. More of the odd skull machines appeared around him, and Outer pulled out something golden from his pocket, raising it up for Undyne to see.

"we're the proud members of the Sans squad, and we fix problems." Outer explained, showing a golden badge to her.

"Fix problems? You just caused on by zapping Horror away!" Undyne snorted, raising an eyebrow. "You're causing even more just by being here!" A spear appeared in her flesh and bone hand, and she begun to spin it, kicking snow up from the force. "Al and I had suspicions that you Sans were causing all of these anomalies!"

"heh. says the fucking robot abomination." Fell taunted her, as Outer slipped the badge back into his pocket, fiddling with something else in his pockets. "look at you, are ya some kind of lovecraftian horror?"

"I am no robot. No, not by a longshot. My systems are all purely clockwork." She growled. His taunts were obviously getting to her, as she raised her hand, about to pull her key out. "I'll give you one more warning. Get back to your timelines or I'll stuff you back into them myself." She snarled. Outer was about to press a button on the machine, hidden in his hands, which Undyne recognized as the thing that probably sent Horror into another timeline, and she prepared to dodge. However, Fell quickly raised his hand, his fanged smile growing.

"hey outer. want to show this idiot what it means to mess with the Sans squad?" Fell said, a huge smile on his face. Outer rolled his eyes, and lifted a hand to facepalm.

"fell, we need to go, do we have to-" He started, before Fell immediately cut him off again.

"don't be so square! of course we gotta beat her face in! we gotta represent the squad!" Fell said, pumping his fists into the air. Outer sighed, putting the machine back. Undyne relaxed slightly, knowing that the chances of her getting snapped into a new timeline were very, very slim.

"Hmph. Well, aren't you a cheery piece of timeline breaking scum." Undyne growled. "Enough chatting, Sans'. I've got more important places to be, and timelines won't fix themselves." With that, Undyne hurled her spear into the snow behind them, making them glance behind them as a flurry of snow sent itself up. While they were turned, an entire array of spears, bolts of cyan, appeared all around her. "Ducking is a good idea at this point." Undyne whispered. The two stared at her, completely speechless as to just how many spears were floating in the air around her.

"Well. Fuck." Fell cursed, and Outer winced. The two immediately did exactly what Undyne told them to do, and hit the deck. "D-do something!" He snarled at Outer as he raised a bone wall. They both heard the thunks of the spears landing into the bone wall, and Outer quickly scrambled to raise blue and yellow skull machines similar to Fell's. It began to shoot at the spears, and both the lasers and spears cancelled each other out, letting only a few shots through.

"I can shoot even faster than those things!" Undyne bellowed over the sound of it. At this point, they were causing a huge lightshow in the middle of a place that would probably attract even more enemies than usual. Fell grunted, straining his magic and shooting his blasters. A spear slipped through the bones, and Outer teleported away with a yelp.

"Not good!" Outer gasped. "F-Fell, this is an A Class Anomaly, this is bad!" Outer said, and Fell glanced at him.

"Wait wait wait, what the flying fuck does that mean?!" Fell asked him, but before Outer could answer, Undyne immediately interrupted them.

"I'm the anomaly?" She said, sounding slightly confused, her spears stopping for a moment. Undyne quickly leaned away from a blast that Fell shot at her, sending her bright red hair blowing away from the wind and impact that was created from the laser.

"Ugh- Well, of course you are! Are you an idiot!" Fell said, his eye sparking into a blood red as he pulled himself to look up over the wall.

"You come into an AU, from a different AU, or, world, and you're neither a part of or affiliated with-" Outer raised his hand again, showing the badge to her once more. "The Sans Squad." Fell shot him a look as Outer let out a yelp, yanking his hands away and dropping the badge. A spear shot straight through it, embedding itself into a tree behind them. Fell growled something about that being a stupid idea in the first place, and Outer looked completely flabbergasted, staring at the gold pieces falling onto the ground..

"I should give myself a team name... How about Between? ... No, Between just doesn't sound right." She growled.

"What the hell is a Between anyways?" Fell yelled. "Some kind of stupid sounding AU? If so, fuck off and go the hell home!" He snarled.

"The Between is a dangerous, mysterious place. While many people, many versions of people have died in there, there's something I've noticed. Not a single Sans has ever died there. And, I can't go home until you're gone. A surefire way to make sure my job is completely done every single time." Undyne explained to them, as if she was talking to a pair of children. She raised her metal hand, spinning a spear as quickly as possible, beginning to create a shield to deflect the attacks that Fell and Outer shot at them. Her attacks began to come slower, as she was focused on blocking them. The spears began to break through the bones, as Fell groaned.

"Same here bucko! So just leave it to the professionals and up yours!" Fell yelled, and Outer nodded, shooting as much as he could. "Oh, and the 'Between' sounds like some sort of restaurant! You guys do Italian?" He shouted, and Outer rolled his eyes. Undyne was about to open her mouth and shout something at him before he countered, "What? No? No you don't? Guess you're a bunch of cheap im-pastas!" Outer gave a shout and hit Fell upside the head.

"Not the time for shitty puns!" Outer growled.

"Every time is time for shitty puns. And I do all of the swearing here." Fell countered. But Undyne wasn't going to let his comment about the Between slide anytime soon, and she slammed into the bones, trying to get close to attack them head on. Outer and Fell immediately ran up, pushing against her attacks to keep the wall up, until a slam sent them flying, pieces of bones flying everywhere. They didn't get a chance to even hit the ground, as they dissolved into dust mid air. Fell rolled into the snow, using his magic to slow his impact into the ground, but a yell made him immediately stop his attacks on Undyne. Not only did his blasters go silent, but so did Outer's, which all turned into dust. "Well... Shit, shit, and even more shit." He whispered, glancing at Outer's direction. His partner was out like a light, and ran up to him, grabbing him.

"You better haul your sorry asses out of Horrortale right now, or I'll put you both out forever." Undyne said, stepping through the wreckage of the bone wall, spears appearing in her hands and a smile on her face.

"Okay, fine. We surrender. But three words, please." Fell sighed, hauling Outer up with both his magic and one arm, the odd timeline machine in his other hand. Undyne stopped her advance, obviously granting him permission, and the smirk on Fell's face grew. "Go. Fuck. Yourself." Fell whispered as he teleported both himself and Outer away to who knows where, leaving behind the bone wall as it collapsed into dust, and the shreds of Outer's badge. Undyne walked up to its remains, picking them up gently. A beeping sound came from her pocket, where she took out the cog-looking machine Alphys had given her to return back to the Between. These Sans were dangerous, and Undyne knew it.

"Mission complete." She said, and with a flash of dark green, it was as if she was never there.

* * *

"Let me get this straight." Alphys whispered. "You ran into three, three different Sans. Two of them were not from the timeline, which explains the paradoxes, and they zapped the local one out of the timeline?" Alphys asked Undyne, who nodded with her words. "This, this... Ugh, okay, this confirms my theory. Sans can move in and out of timelines, and the Between, which explains why not a single one has died here. They claimed that they were a part... Of the Sans squad. Alright. Sans Squad, that means there's a lot, lot more of them." She sighed, rubbing her temples and picking up a journal, taking a stub of a pencil and beginning to write in it. "Sans Squad, one of the mysteries solved. They've been causing these anomalies..." Alphys whispered. "Fell and Outer, two proven members of this Sans Squad, judging by the sound of it, there's many more Sans." She pushed off of her desk with her feet to another one where Undyne had placed the badge. Alphys' entirely mechanical arm extended, piecing together the badge as best as she could.

"Right so far." Undyne shrugged, leaning over her shoulder. Alphys had already assembled the thing almost perfectly. The middle of the badge caved in from where Undyne had speared it clean through. Undyne let out a sigh. "Sorry, I destroyed that thing maybe a little too much." She sighed, and Alphys merely shrugged, moving a piece in closely.

"Done." Alphys said, before a small beam of light came from her metal arm, fusing the pieces together, before picking it up gently. She took her journal, putting the badge onto the page. "And, there." She muttered.

"What's that?" Undyne asked her, pointing at the journal. The page they were on had the title of Sans Squad, with the list of Fell and Outer's names on it, the badge now stuck onto the adjacent page. Alphys flipped to the front of it, which appeared to look more like a diary than a journal.

"A collection of the things I've learned in the Between. It documents the Errim, their weakness and attraction to light, the number of people who have died in here both before and after I arrived, who has survived, a list very short, with only three names on it. Yours, mine, and all Sans. Oh, and how Chara is the reason why we're both stuck in here. Interesting, right? I plan to have new people who we will attempt to save read it to gain knowledge of the timelines and the Between." Alphys explained to Undyne, flipping through the pages as she spoke. Undyne opened her mouth, before a blaring alarm sounded, and Alphys' lab flushed red. "Another one?! So soon?!" She yelled, running to the cameras, Undyne at her side. "It's a human. Frisk or Chara, and I doubt it's Chara. Come on, lets go get them before the Errim do!" Alphys said, running past Undyne and heaving open the heavy stone door of her lab, followed by Undyne, who slammed the door shut before continuing with her.

"What do you mean another?" Undyne gasped as they ran. Alphys was surprisingly fast for someone so short.

"Someone else who's fallen into the Between. The rate is increasing. You appeared only three weeks ag-"

"Three weeks?!" Undyne exclaimed.

"It took me most of that time to piece you back together into something you could, you know, live with. That's not important now, since you're alive and all. But appearances in the Between were spaced months apart, sometimes years, and this is unnatural! Whoever's down there, I'd love to keep with us, but like I said, I don't want to keep anyone from coming home. When you've been changed beyond recognition, like you had been, you can't return. It just messes everything up. Suddenly you look normal, the next you've got a bunch of these metal bodyparts, it's not good." Alphys panted, explaining it to Undyne as they ran through the stone tunnels. They took a route that dipped downwards very abruptly, and began to splash through the dust water. "Anyways, we're close. Lets hope they're alright." She said, raising her hand to give off a small light so they could see the person. "Oh! There!" Alphys said, pointing. "Get them, I'll keep watch for the Errim."

Undyne sloshed through the water, and it disturbed her that she was basically walking through a lot of dead people. How disgusting. Undyne leaned down, picking up the limp body. "Are they dead?" She said, walking back up to Alphys, who quickly grabbed one of their hands, checking for a pulse with her cold metal fingers.

"... No, not dead, but they might be if we don't get them back to the lab." Alphys shut off her light. "Move quickly and quietly, I'd rather not deal with any Errim anytime soon." She explained, running as fast as she could, with Undyne trying to protect her precious cargo close behind. It didn't take long before the lab door was in sight, yet the growls of the Errim were close behind them. Alphys' arm extended, and she ripped open the door. She bolted in, and Undyne slid in right after her. With that, Alphys closed it and locked it, as a slam was heard against the stone. "And, safe." Alphys whispered. "Put them down on the bed over there." She said, and Undyne rushed to do her bidding, putting the child down onto the bed. The moment Undyne saw who it was, she stopped, her eyes widening.

"... Alphys." She whispered.

"What is it?" Alphys asked, hauling a huge box of her tools out. "Are any of their limbs gone?"

"No, in fact, they're nearly untouched... But that's not the problem. This is... This is a Chara!"


End file.
